Traitor
by psquare
Summary: Post s3 AU. Castiel is sent to Hell to rescue Dean Winchester and kill his brother, the Boy King. What he finds, instead, changes everything. Sam/Castiel.


**_A/N:_** This was written for the Sassy Secret Santa exchange on tumblr, for jaredcortese.

**Warnings: **Spoilers till the end of s3 and for the beginning of s4, some torture/gore, some swearing, lots and lots of weirdness, metaphor-abuse.

**Prompt: **Sam became the Boy King of Hell after season 3, and Cas is sent to kill him as he retrieves the Righteous Man. Except, the King isn't exactly the root of all evil he was expecting. He actually seemed awed that something as inherently good as an angel existed at all.

**Disclaimer: **I don't own _Supernatural_ or any of its characters.

_**Traitor**_

_there's sam._

_there's sam, and another man—a luminous man, whose every moment is followed by a halo of golden light that hurts dean's eyes._

_there's sam, that luminous man, and beyond them is a gaping maw of endless darkness, ringed by teeth that's dripping blood and entrails, echoing screams and the wet sound of tearing flesh._

_beyond them is freedom._

_dean gathers his misshapen, dismembered body together, and stumbles towards it._

* * *

><p>Heaven had grown complacent. It had been a long, long time—countless millennia—since the angels had had opportunity to invade Hell. They had forgotten a crucial weakness, a weakness that irreversibly crippled their attack, that ultimately led to their defeat.<p>

They couldn't use their true forms in Hell.

Human vessels were a curious thing; Castiel remembered the days when they were taller, infinitely stronger, and possessed a sort of uncomplicated faith that was only compounded by cosmic machinations, rather than being broken by it. Now, they were... lesser, embittered and shrunken, and the angels wearing them hadn't seen battle in a long while. The garrison sent to rescue Dean Winchester had been decimated almost instantaneously.

Only Castiel remained.

He was not sure why he was spared; the purpose of his garrison could not have been more apparent, so he was not being kept for information. And if they believed he could be _tortured_ into submission, he would show them what it meant to be Heaven's warrior. He would _show_—

The fleshy tendrils that were moulded to his skin and twined around his heart twitched, and he felt a distant scream at the edges of his awareness. It was unrelenting, the agony that his vessel's soul was in—but also distant, like waves against a cliff face. Castiel made no further note of it; once he was dead, James Novak's soul was destined for Heaven.

Long fingers gripped his chin and lifted his face. They were not dark and burning, scoring patterns across Novak's skin, but _human_—soft, almost gentle.

Castiel met the eyes of Sam Winchester.

He recoiled, regardless of the appendages coiled in his body; they ripped through more organs, and for an unguarded moment, Castiel might have even joined Novak in the screaming. He recovered eventually, blood dripping in slow, thick strands from his lips. When he opened his eyes (_when had he closed them?_) Sam Winchester was still holding his face, smiling sadly.

"So that proves it, then," he said.

Castiel jerked his chin out of Sam's grip. "Away, you _abomination_," he spat. "I may have been sent to raise your brother, but I have no obligation to extend the favour to _you_."

Sam only continued to smile. "Of course you won't. And you won't kill me, either." He looked away distractedly. "I can help you."

"Help." Castiel raised his eyebrows. This human looked tall and innocuous, but Castiel could _see_, couldn't he? Demon blood like maggots crawling through his veins, tainted from birth by evil that he had finally chosen to embrace. His very _breath_ exuded a power that—

"Yes, help. As in help getting my brother out of here." Sam quickly glanced behind him, then turned to Castiel. "Listen, they're coming. Let me do all the talking; just... go along with me, all right?"

Castiel stared.

"All I ask of you," Sam said slowly, clearly, "is faith."

As soon as the word had left his lips, the air around them grew thick with the miasma of... a hundred, five hundred demons. Sam drew in a deep, deep breath (and Castiel imagined he breathed _in_ those demons, drawing them to entwine with him as much as Castiel was now imprisoned in the very fabric of Hell). He seemed to grow in stature, and when he spoke, his voice rang true and loud and clear: "We have nothing more to fear! We have defeated the mightiest of Heaven's warriors—and now we shall prove that not only can we slay them, we can _toy_ with them." He smiled at Castiel then, a slow smile spreading like a bloodstain on his face—Novak quailed, and a part of Castiel quailed with him. "And what better way to start than with... _this_."

A million jeers surrounded them, every molecule of Castiel's body vibrating with their mirth. The tendrils inside him twisted and undulated, reaching in, in—

"But that is for me to do alone!" Sam roared, and suddenly the jeers and the laughter stopped, and the tendrils retreated until they were just barely holding Castiel up.

"I will take this angel," Sam said, "and bring back to you a broken mockery of what it was."

The demons—and the tendrils—retreated as Sam gestured for him to rise. Castiel fell to the ground spitting blood and bile, clutching weakly at handfuls of dust. He would recover from what his vessel had endured, but it would take time, and a lot more power than he possessed right now—

Hands went under his shoulders, gently pulling him to his feet. It was Sam, yet he was not touching him—it was an exercise of telekinetic ability that Castiel had not thought him capable of.

"Come," Sam said regally before turning and walking away. Invisible hands gently prodded him forward, and Castiel shuffled awkwardly behind Sam, like a dog on a leash.

The psychic touch did not leave him for one second.

* * *

><p>"Sorry for the theatrics back there," Sam told him after they had walked for some time. "Had to sell it, and besides," now he was smiling that soft smile again, a quick flash of creases in his cheeks, "it's the only kind of thing they'll respond to. I mean, <em>you<em>, of all the—you should know, right?"

Castiel could barely spare the energy to walk, but Sam had done him no harm so far—he was at least owed an answer. "I suppose. Devotion and fanaticism are separated by a very thin line."

"Right."

They walked in silence for a little while after that, dead, featureless dust bowls stretching around them as far as they could see. Castiel sensed there was a reason for this aimlessness; sensed that it was because Sam was nervous, maybe even _afraid_. This seemed astonishing—this creature was the king of the beings that had destroyed an entire garrison of angels, a creature that was literally _cradling_ Castiel with invisible hands, carrying him to deliver any fate he wished to.

And yet—

"Should have known it existed," Sam said suddenly.

"What?"

"Heaven. Angels—you. I mean, Hell and demons exist, and it only makes sense, right? But there was so little to go on, and sometimes it was so hard to _believe_—"

"You prayed," Castiel said, not without wonder.

"In a way, yeah." Sam ducked his head and smiled shyly. "In fact, I still do."

(_all i ask of you is faith_)

Castiel could barely comprehend what was happening, but he started tentatively, "Samuel, forgiveness is offered to all those who truly ask for it, and those—"

"Dean." Sam turned, spread his arms, and Castiel felt him let go of his psychic hold. Castiel just barely managed to stay on his feet. "Where were you looking for him?"

"You do not know?"

Sam smiled. "They don't trust me fully. Not yet, anyway."

Castiel remembered a battlefield, several thousand years ago, when the barriers between the planes were porous, and God appeared before them in a multitude of ways. He remembered a broken general being charioteered by God Himself; remembered when that general, once crippled by doubt, stood tall and slew millions at His word.

Duty was paramount; Castiel had a mission he needed to complete, regardless of whom he had lost and what he still had to lose.

And if that meant working with the king of Hell, so be it.

"You have a window to your brother inside of you, Sam," he said. "Use that connection to find out where Dean Winchester is."

"I don't—" Sam started, but by then Castiel had already placed two fingers on Sam's forehead, and Hell dissolved around them.

* * *

><p>In a featureless motel room (<em>no, not quite—see those green marks on the wall there? those were made by a little boy too afraid to use his crayons on the wall, but tempted to give a go anyway<em>), a man (_father_) lay on one of the beds, covered by bloodstained (_a werewolf hunt gone wrong_) sheets. His breath was grating wetly in and out of him (_broken ribs, pneumonia, he was in a bad way, he was dying, dying, dying—_), and the older boy (_just ten years old, too fucking young to understand anything, but old enough to __**know**_) wringing a wet washcloth and dabbing at the man's skin helplessly. The younger boy (_so small, so ignorant_) knelt next to the man's bed, hands clasped, and asked the older one to join him (_and he almost did, he almost, almost—_)

_God—_

_Please—_

_if you're listening—_

_let my family be okay._

_if you're listening_

_**if you're listening—**_

Another motel room (_sam's economics textbook buried under dean's pornos in the corner_), a church (_pastor jim gently taking him through the basics of latin while dean made faces over his shoulder_), a dusty living room (_sam holding the most important letter of his life and the world spinning around him_), a room, cramped, filled with beds and people and books (_and sam, thinking which hunt, what death, death, death, death_), **fire everywhere**, (_his love, his mother, his life_), and through it all, through each and every one of them—

—prayer.

Castiel was collapsing into himself with the burden of it, sucking in all that was and that will ever be like a dying star (_aren't they just words though just words just_), reducing himself to a infinitesimal singularity point and then reversing, bursting, exploding into a whole new universe.

When Castiel awoke, his hand was intertwined with Sam's, and they could hear Dean screaming in the distance.

* * *

><p><em>here's sam.<em>

_here's sam, and another man—a luminous man, whose every breath is a pulse of light laying waste to the darkness that he'd given himself to._

_here's sam, that luminous man, and between them and their joined hands, none of hell shall pass._

_with them lies freedom._

_sam reaches out with one hand to save his brother._

_**Finis**_


End file.
